Use of an ultra-high resolution magnetic spectrograph for materials research

A brief description is given of a magnetic spectrograph for RBS and ERD analysis with MeV beams, delivered by a Tandem accelerator. With a number of examples of thin layer analysis it is shown that the spectrograph is uniquely suited for the measurement of concentration depth profiles up to a depth of about 50 nm. The positions of light and heavy atoms in epitaxial layers can be determined by using blocking, or channeling/blocking geometries in ERD or RBS measurements. Such determinations are especially interesting for samples with shallow interfaces and delta-doped layers. It is also shown that the impact-parameter dependence of energy loss and charge exchange in ion-solid interactions can be determined from measurements at samples with submonolayer coverage of elements at the surface, single crystalline samples, or (in transmission geometries) very thin layers. Some features of this spectrograph are compared with those of a selection of other high-resolution analyzers.